If you have an ATT phone (other brand cell phones don't do this), turn it off, not just the ringer. The phone will continue to check in with the ringer off. Balanced mics will deal with this better than the unbalanced rig you have. Balance refers (in my limited understanding) to sending a signal and its negative which is then re-inverted at the receiving end. The two are added together so the signal is doubled and the noise, which comes in after the first inversion, canceled out. It is possible (I believe) to do this using the shielding (if any) of your cable against the inverted signal but takes some research and development. Church might be able to pull it off for you. The R-09 has balanced inputs so if you got some different (balanced) mics with xlr or mini xlr connectors it is likely you won't hear this again.
It also might not even be the recording. Could be the sound was coming through the PA. Musicians with powered on ATT phones in their pockets get picked up by unbalanced guitar cords. This sound came through the PA at Phish Red Rocks last year and countless local shows.
If you don't personally have an ATT phone, this won't happen too often. It hasn't happened to me with my unbalanced rig yet.
ATT presumably is breaking FCC regulations by allowing this crap to happen.